Boat Security Guide

This guide is just that — a guide. It contains suggestions gathered from considerable research into ways to prevent boats and their equipment from being stolen. If you employ these suggestions you may significantly reduce your vulnerability to theft. But keep in mind; if Fort Knox were theft-proof, they wouldn’t guard it.

Boat Security Guide _ Periodically Peregrine (Download)

In our view, there are two basic elements to theft protection: exposure and delay. If the thief must work in an exposed location or must spend more than about 10 minutes making a hit he will generally look for easier targets. Our suggestions focus on these elements. They will usually deter all but the professional criminal.

Security Guide or not, you are the single most important factor. You have more to lose than anyone else if your boat or equipment is stolen. Inflation [10+% at the time] will prevent you from replacing your boat loss without hardship and insurance companies are becoming increasingly reluctant to pay claims on equipment losses without evidence of forced entry (or stated another way: theft protection.)

So, read the guide through, select the actions you consider best in your circumstances, and carry them out. You may reduce your risks, you’ll contribute to slowing the growth of insurance premiums, and you’ll probably feel better in the process!


Delay is frequently easier to achieve than exposure with the slip situation the way it is today. The two are not independent though. Commonsense would indicate and its true that the less exposed your boat is to observation, the more delay you must incorporate in your theft protection measures.

Locks are your first line of defense.

  • Buy quality locks — don’t scrimp
  • Look for hardened shanks — they are harder to cut through 
  • Buy the shortest shank that will do the job — bicycle locks are out 
  • Buy locks with shanks that just fit the hasp
  • Buy locks that will stand up in the marine world — take your magnet, if it sticks to the lock — pass it up
  • If you plan to use several locks — buy them “keyed alike” — it makes opening up simpler

 Don’t waste a good lock on a lousy hasp.

  • When the hasp is closed — the fasteners should not be exposed
  • If they are, drill out the slots or fill them with epoxy putty to make removal slower.
  • Don’t attach hasps with wood screws — use machine screws or bolts with backing plates and nuts
  • If nuts are exposed — peen the threads flat.
  • If you must rely on a hasp — use one size larger than looks reasonable

Every hatch, entry, door, cuddy, or locker should be locked, preferably from the inside so that no purchase for pry-bars or jimmies is available. Also, if you lock from the inside, you can reduce your padlock investment.

Modern aluminum and polycarbonate hatches without built-in lock points are very vulnerable. Frequently, bouncing on the hatch will compress the gasket enough to release the latches. If the latches don’t release, the self-tapping sheet metal screws outside holding the polycarbonate in place can be withdrawn quickly. So, at least, drill out the slots and consider pulling the screws and coating the threads with locking compound. These hatches can be locked from below by making a wire lanyard with loops at each end. One loop goes under the hatch brace pivot bolt (the one on the hatch). The other loop is shackled to an eye bolt installed in a sturdy location under the hatch. Wire is necessary to prevent stretch and to resist thin knives slid in under the gasket.

More traditional hatches can be handled the same way or can be secured with cross bars or large, old—fashioned drop-latch bolts attached on the inside with heavy hardware.

Seat—lockers on cruising boats can be secured with wire lanyards with rope tails. These are run into the cabin where they can be secured on cleats. This has the added advantage of removing clothes and skin ripping hasps from the cockpit.

Hinged seat hatches should have their hinge pins peened to prevent removal. Hinges should be attached just like hasps and should be over-sized where practical.

Sliding windows should have vertically installed latch bolts or can be kept closed like patio doors with a wood or metal rod in the slide track.

Anchor lockers can be secured like seat hatches. They can also be secured by locking a bar through your toerail over the locker. If you don’t have toerail or a convenient path to route a lanyard, consider locking the anchor inside the locker. Put it on top of the rode and lock it directly to the ring bolt the rode is secured to.

The second line of delay in the war against theft is to prevent the boat from being moved. Your engine or sails can be used to move the boat to a secluded location for stripping or they can be stolen themselves.

Outboard motors

  • Should be locked in the tilted up position (clearly this can create other problems)
  • Remove your distributor rotor (if there is one) or take the spark plug cable out when you leave
  • For long absences take your propeller too
  • Use a patented locking bar to keep the pad nuts from being loosened
  • Lock portable gas tanks on board
  • Use gas-line locks to prevent thieves from using their own gas supply

Inboards are harder to steal but it has happened.

  • Lock your engine access hatch when you are away
  • Drill one or two mounting studs and put padlocks on the holes (remove underway)
  • Gasoline engines should have the rotor removed
  • For long absences take the coil or wires too.
  • Out-drives which are not raised should be locked —— hard over left or right
  • Starter circuits should have hidden, vapor-proof switches between the engine and battery or battery cables should be removed
  • Diesel engines should have fuel shut-off valves that can be locked shut or that are located in a locked compartment.
  • Hand-cranks should be hidden away or removed from the boat

On any boat it is a good idea to remove the batteries but that is often easier said than done. So, make sure that the battery compartment is lockable.

A disabled engine makes no difference if you leave usable sails aboard a sailboat.

  • Remove all sails from the boat
  • If you can’t do that — stow them all below — run a chain through the clews and lock them to the boat structure
  • If the main must be left on the boom —- run a chain through the headboard under the boom and lock both ends together

Additional steps to prevent your boat from being moved include: 

  • Remove your tiller — store it at home or locked below -— this will usually stop the outright thief; Lock your wheel hard over with a heavy chain
  • Chain your boat to the dock — use a chain longer than the dockline it is nearest to — make sure the chain cannot be lifted over whatever it is locked to
  • Boats on moorings should also receive the chain treatment

Trailerable boats and their trailers have special problems which require special solutions.

  • When the trailer is attached to a tow vehicle — lock them together and lock the vehicle
  • When the trailer is unattached use a commercial hitch lock or buy a spare ball,cut off the threads place it in the hitch and lock the hitch lever down
  • Unattended trailers should be locked to an immovable object – encourage your marina or state park service to install tie-down rings
  • Boats on unattended trailers should be chained to the trailer too
  • Prevent unauthorized launchings, trailers attached to vehicles left unattended should be backed tightly against a wall or fence
  • Consider chaining and locking all of your wheels to each other and the trailer frame — so they are there when you come back and the trailer can’t be rolled
  • If you have a dolly jack raise it to full height when you leave and lock it there
  • Trailer winches and rollers are becoming targets for thieves – since replacement is rarely required, peen the attachment bolts

Finally, remove hard to secure, high value items such as electronic gear and take them home with you when you leave


Exposure comes in two categories: exposure to observation and exposure to detection. These are closely related but you must take active steps to see that the are both a problem for the thief. Delay buys you a lot of exposure to observation, but as much as possible, avoid leaving your boat, trailer, or equipment in a secluded location.

  • Park boats on trailers where you and your neighbors can see them
  • Keep your boat at a lighted marina or yacht club.
  • Install dock lights on your own dock
  • If you moor behind your home — use wire-guarded spotlights to illuminate your boat

Once you have put your boat where it and a thief are easily observed you need to provide for exposure to detection. Exposure to detection has two forms: pre-theft and post-theft.

 Pre—theft exposure to detection can be achieved with a good alarm system If you decide to use an alarm — don’t buy the first one you see without shopping around a little — an alarm is not an alarm is not an alarm.   Alarms come in three general types

  • Those that go off — sound until the electricity runs out or the trigger switch is closed
  • Those that go off — and have a holding relay which keeps the alarm going after the trigger switch is shut — until the electricity runs out
  • Those that go off – sound past trigger closure and the shut off a few minutes later — ready to go again

Resettables are best, but most expensive. The question is, what is your boat worth to you?

  • All wiring in alarm systems should be hidden
  • Horns and sirens should be LOUD
  • Power sources should be locked up — open boats with their batteries removed will have to use lantern or hotshot batteries
  • Disable switches — the ones that allow you to get aboard without making your neighbors angry — should be hidden and confusing to operate — wired backwards — multiple identical switches some of which trigger the alarm — be imaginative
  • Consider hooking your alarm system to you interior and exterior lights thieves just love lights
  • Magnetic switches are your best bet in the marine world — there are others available which may suit your situation better — look into these when you are shopping around
  • Lastly, think twice about using alarm stickers — the thief may just take your boat instead of breaking into it

 Other pre-theft exposure aids are:

  • Work with marina managers to get patrols established
  • Work with other boat owners to question strangers on the dock
  • Call the police and encourage them to patrol your area — then cooperate when they do

The threat of post theft detection will sometimes make the thief who plans to fence your gear leave it where it is.

  • Label everything!!!!!!!!!!! Engrave hard stuff — use water-proof marker on the soft stuff
  • Ask your police about Operation I.D. — if they participate – use the number they give you — if not, DO NOT use your Social Security Number, DO use registration number, or documentation number plus your name or the boat’s name
  • Put identification information in your boat or dink in two places one out in the open — one in a hidden location under one layer of 6 oz glass cloth and clear resin which is then painted over
  • Don’t discuss those locations with anyone — except a buyer who has given you a certified check and after it has cleared.
  • Paint state numbers on – peel-offs make easy rip-offs easier
  • Never, never, leave ownership papers aboard — failure to produce them when requested can ruin a thief’s entire day


There are other measures you could take but these that we have outlined will go a long way toward saving you the financial loss and personal frustration (even grief) associated with having your boat and equipment stolen. You read it, now go out and do something about it!

4 responses to “Boat Security Guide

  1. Very good advice, especially about the custom outboard lock. More modern outboards have holes in the clamp eyes where you can insert the correct size lock, keeping it from being able to be unclamped, but mine doesn’t have these holes and the clamps even when twisted inwards aren’t close enough even if I were to drill holes.

    I have my cabin locked and the boat locked and chained to a piling off the bow. Nothing will stop a truly determined thief, but after having my boat moved and having to recover it twice now I added the chain from the ground tackle on the piling. On the upside, my outboard is old and looks like a POS despite being completely refurbished by a certified Mercury tech (who I bought it from). It’s covered with a big plastic bag to give it partial protection from the rain. Found it removed once and stuffed in the cockpit, maybe a would be thief took a look at it and said forget it.

    Sad to have to chain the boat to the dock, the boating world is usually filled with nice people, and it’s boat access only to where it’s moored.

  2. Any tips on how to make the fenders attached to your boat at the dock theft-proof? We are about to invest in two large ones costing $150 a piece for our houseboat to keep it from getting beat to death against the dock. It seems people only use rope and dock line to hang fenders, one snip with a pair of scissors and they’re gone. We’d thought about trying to rig up something with weatherproof steel cable if we can find it, and a padlock. Any ideas?

    • Shirley,
      In years of cruising, we have never heard of folks having fenders stolen — I’m sure it happens, but not enough to become a persistent topic of conversation in our cruising environs. That said, back when we still cruised with folding bikes aboard, we did use our bicycle locks to secure our fenders in a couple of worrisome places. These were cable locks that could be threaded through the eye on the fender ends. We left them loose enough they would not interfere with natural fender movement. One problem with these locks is getting lost keys replaced is close to impossible. We chose combination style locks and kept them well lubricated. C&J

  3. Pingback: Nice to be Referenced | Periodically Peregrine

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